BEIJING, JAN. 15 -- China's restrictive birth control program is faltering because of ineffective implementation and strong resistance from farmers, said an official report obtained today.

The report said that despite renewed efforts last year to bring the birth rate under control, China's population growth has surpassed planned quotas for two years in a row, requiring new measures to curb the increase.

Experts said that at its current rate of growth, China's population will reach 1.287 billion by the end of this century -- 84 million more people than the government had planned.

The report was prepared by Chang Chongxuan, vice minister of the state family planning commission, for presentation to family planning directors attending a seven-day meeting that opens here Saturday.

The report said that in some areas resistance to birth control is so strong that farmers have beaten up or even killed local family planning officials.

Other reports have indicated that many of the population problems are the result of rural reforms, which provide incentives for increased production, thus encouraging farmers to seek more workers.

The 1987 birth rate is reported to be the highest in the past four years.

Chang's report cited several reasons for the increase in the birth rate, including a growing number of early marriages, an increase in the number of women of child-bearing age and ineffective family planning organizations and officials in rural areas.

It said that about a third of the country's counties are still "backward" in family planning work.

The People's Daily, the leading Communist Party newspaper, said in a front-page article yesterday that farmers resist the birth control program because they need more farm hands.

The paper said economic reforms in the countryside that abolished communes and returned the control of farmland to families have heightened the need for male labor. "A family must have at least one boy . . . and the more and earlier the better," it said.

The paper quoted a 54-year-old peasant living outside Beijing who explained that his 4-year-old son was not his first child. "He's my seventh child," the farmer said. "The other six are all girls." There are thousands of such cases, the paper said.

The People's Daily also mentioned the problem of China's growing "floating population" of construction workers, small business people and others who belong to no fixed work unit and who cannot be easily controlled.

Vice Minister Chang's report called for new measures to improve the birth control program. It said contraceptives must be distributed more efficiently and that propaganda and educational work must be strengthened. The report proposed an increase in the number of trained family planning workers and mentioned new regulations prohibiting early marriages.

The legal age for marriages in China is 22 for men and 20 for women. But more and more couples, particularly in rural areas, marry before reaching the legal age.

Couples who pledge to have only one child are given subsidies and other benefits. If a couple violates the pledge, the subsidies are withdrawn and fines imposed.

But some peasants have become so wealthy that they can easily afford to pay the fines, according to Chinese press reports.

Some provinces and cities have issued regulations to penalize members of the floating population who violate the one-child guideline.

In Shanghai, workers who do not belong to a fixed work unit and have more than one child are fined as much as 2,000 yuan ($540), the equivalent of more than 1 1/2 years' salary for the average worker.

The Chinese government argued that a "one-couple, one-child" policy is necessary because of China's already huge population, lack of arable land and backward economy. But the policy has been controversial in recent years.

In 1985, the United States, reacting to reports that the Chinese were resorting to coercive birth control methods, such as forced abortions and forced sterilizations, began withholding contributions to the United Nations' Fund for Population Activities.

The fund supports the Chinese family planning program, but U.N. officials said the funds that go to China are devoted to education and training.